This application is based on Application Nos. HEI 9-279975 and 10-92739 filed in Japan, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image forming apparatus provided with a function for binding a plurality of sheets of printed document images.
2. Description of the Related Art
Conventional image forming apparatuses provided with a document binding function are known, such as that disclosed in U.S. Pat. No. 5,257,081. In this prior art is disclosed a copying apparatus provided with a simple binding function whereby a copy sheet onto which a cover document has been copied is folded in half, a set of copy sheets to which the content documents have been copied are interposed between the two halves of said folded cover sheet on the interior side thereof, and the document is stapled along the fold, as shown in FIG. 20(a).
Binding devices are known which have been provided with a binding function whereby a set of copy sheets bearing copy images are interposed between a special cover sheet previously coated with binding paste, which is melted via heat from a heater to produce the bound document shown in FIG. 20(b).
The copying apparatus disclosed in U.S. Pat. No. 5,257,081 is disadvantageous, however, inasmuch as when the thickness of the set of copy sheets of the content documents becomes greater, the copy sheets of the content documents protrude from the edges of the copy sheet of the cover document, such that the binding region becomes unsightly.
Furthermore, the operating cost is increased since special cover sheets are required in copying apparatus which bind documents using a special cover sheet coated with pre-applied paste as previously described. A still further disadvantage is the higher cost of the apparatus and increased size of the apparatus due to the requirement of a heater to melt the paste.
An object of the present invention is to provide an image forming apparatus capable of binding a set of recording sheets on which document images have been printed so as to produce a high quality bound document at low cost regardless of the thickness of said recording sheet set.
These objects are attained by a first aspect of an embodiment of an image forming apparatus binding a set of recording sheets on which document images are printed by interposing said set of recording sheets between a front cover and back cover of cover recording sheets, said image forming apparatus being provided with a folding device folding said cover sheet in a direction perpendicular to the sheet transport direction, and a first fold-control device controlling said folding device so as to fold said cover sheet into three sections of a front cover, spine, and back cover.
The aforesaid image forming apparatus further comprises a second fold-control device controlling said folding device so as to fold said cover sheet recording sheet into two sections of a front cover and a back cover, and a switching device to switch between said first fold-control device and said second fold-control device based on the number of document sheets.
The aforesaid image forming apparatus further comprises a punching unit disposed at a predetermined position in the sheet transport path for punching holes in the cover sheets and recording sheets on which the document images are printed, and a stapling device for stapling the set of recording sheets accommodated between said cover sheets at predetermined positions along the fold of said cover sheet.
A second aspect of an embodiment of the image forming apparatus which finishes recording sheets on which document images are printed provides a punch unit disposed at a predetermined position in the sheet transport path for punching holes in said recording sheets with a specified operation timing, and a punch control device controlling the operation timing of said punching device so as to punch holes in the outside recording sheet and the inside recording sheet, when said sheets are folded in two, at different hole positions.
A third aspect of an embodiment of the image forming apparatus which finishes recording sheets on which document images are printed provides a punch unit disposed at a predetermined position in the sheet transport path for punching holes in the recording sheets with a specified operation timing, and a punching control device controlling the operation timing of said punch so as to punch holes at different positions each predetermined number of sheets.
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate specific embodiments of the invention.